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Sources of Crime Data: Uniform Crime Reports and the National Incident-Based Reporting System

Two major sources of crime statistics commonly used in the United States are the Uniform Crime Reports (UCR) and the National
Incident-Based Reporting System (NIBRS).

Uniform Crime Reports

The UCR is the FBI’s widely used system for recording crimes and making policy decisions. It has tracked data on seven crimes
since 1930: murder, robbery, rape, aggravated assault, burglary, theft and vehicle theft. In 1979, the UCR started reporting
on arson. Nearly 17,000 law enforcement agencies report UCR data to the FBI but those data have several limitations that make
them unsuitable for analyzing local crime.

National Incident-Based Reporting System

Crime data from NIBRS (as of 2004) come from 5,271 law enforcement agencies that represent about 20 percent of the total U.S.
population. NIBRS is the result of the FBI's efforts in the 1980s to revise the UCR.

Impact of NIBRS on Law Enforcement

NIBRS significantly expands officers’ ability to record data about a specific incident, which gives leaders a much fuller
understanding of crime. As a result, a mayor’s policy advisor or a police executive can look at NIBRS data alone or combine
them with other citywide data, analyze them, and gain a more descriptive view of criminal activity in thecommunity. NIBRS data help law enforcement gather better evidence to develop effective solutions and practices.

Impact of NIBRS on Research

Assess dual arrest data. Researchers used NIBRS data to examine the factors that influence police decisions to make arrests in domestic violence incidents
and the prevalence of dual arrest across the nation. [1] They found that dual arrest occurs more in same-sex than in heterosexual relationships and in states that have mandatory
arrest policies but no primary aggressor provisions. [2] The researchers suggest that if a state wants to minimize dual arrests, agencies may wish to institute primary aggressor
provisions, change mandatory arrest policies to preferred arrest policies, and educate officers about relationship dynamics
in same-sex relationships. (Read the full report Explaining the Prevalence, Context, and Consequences of Dual Arrest in Intimate Partner Violence Cases (pdf, 207 pages).

Examine drug distribution. A 1999 study used NIBRS data to examine rates of drug sales and distribution in three Virginia communities. Police identified
drug sales that crossed jurisdictional boundaries and were able to develop policies and protocols to capture drug offenders.
[3]

Notes

[1] Dual arrest occurs when an officer arrests multiple parties in an incident as mutual combatants.

[2] A primary aggressor provision instructs officers to arrest only the main offender in an incident.